Centromere evolution and organization in Drosophila

Centromeric satellite DNA FISH in Drosophila mauritiana. Image taken by Ching-Ho Chang (unpublished).

We are interested in the evolution of centromere organization in Drosophila. Centromeres vary in size and complexity across organisms ranging from a single nucleosome in budding yeast to large alpha satellite enriched centromeres in human (Allshire and Karpen 2008). We currently know little about the detailed organization of most eukaryotic centromeres because they are typically buried in repeat-dense heterochromatic regions and are rapidly evolving. We recently collaborated with Barbara Mellone’s lab at the University of Connecticut to combine single molecule long read sequencing, ChIPseq with the centromeric histone variant (CENP-A), and extended chromatin fiber fluorescence in situ hybridization (FISH) to reveal the detailed organization of centromeres in Drosophila melanogaster. We discovered that centromeres are islands of transposable element (TE)-rich DNA embedded within large blocks of tandemly repeated satellite DNAs. Our current projects involve studying how these centromeres evolve over short evolutionary timescales, and particularly, how transposable elements shape molecular and evolutionary aspects of centromere organization.

Figure 2 from Chang et al. 2019 BioRxiv.

Chang, C-H^*, Chavan, A*, Palladino, J.*, Wei, X.^, Martins, N.M.C., Santinello, B., Chen, C-C, Erceg, J., Beliveau, B.J., Wu, C-T, Larracuente, A.M.#, and Mellone, B.G#. 2019. Islands of retroelements are the major components of Drosophila melanogaster centromeres. In revision PLoS Biology. BioRxiv Epub 2/1/2019. doi: 10.1101/537357.

This work is supported by an NSF CAREER (MCB) award to AML.

Collaborators: Mellone Lab, Wu Lab